MM → Inches
216 mm to inches
216 millimeters equals 8.503937 inches — or about 8 1/2" (nearest 1/16″).
Decimal
8.5039 in
Fraction
8 1/2"
Centimeters
21.6 cm
Feet
0.7087 ft
mm
8.503937
in≈ 8 1/2" (nearest 1/16)
1 in = 25.4 mm · tolerance ±0.0001
Formula
To convert mm to inches, divide by 25.4:
inches = mm ÷ 25.4
inches = 216 ÷ 25.4 = 8.503937
Why 216 mm = 8.5039 in
Since 1 inch is defined as exactly 25.4 millimeters, 216 mm converts to 8.503937 inches. Rounded to the nearest 1/16″ that's 8 1/2", which is what you'd read off a standard imperial ruler.